The elucidation of the mechanisms of action of biochemical systems on a molecular level is based upon a complete understanding of the interactions among various components in the system. In a very large number of examples such as the study of enzyme catalysis the reactions to be studied involve the interaction of small molecules with biomacro- molecules. Nuclear magnetic resonance (NMR) spectroscopy is an attractive method for the study of this type of reaction because it offers straightforward techniques for the detailed investigation of the structure of both the small and large molecules in solution as well as techniques for the study of the dynamic aspects of molecular structure and interaction. To date, however, NMR studies of the kinetics and mechanism of enzyme catalyzed reactions have been restricted to the study of inhibitors and substrate analogs. We propose to use NMR methods to study enzyme substrate reactions by combining Fourier transform techniques for rapid NMR spectral acquisition and rapid mixing techniques for NMR. These techniques will be applied to the study of the enzymes lysozyme, sucrose phosphorylase, and aspartate transcarbamylase with the aim of elucidating the kinetics of formation of and the structure and environment of enzyme substrate complexes.